Abstract: Provided is a measurement apparatus which includes: an illuminating unit for grayscale image configured to illuminate an object by two light sources among a plurality of light sources specified based on a periodic direction of streaks on a surface of the object and arranged opposite to each other with respect to an optical axis of the illumination unit for distance image and a processing unit configured to correct a pattern projection image based on the grayscale image obtained by imaging the object illuminated by the two light sources.

Abstract: The present invention provides a measurement apparatus which measures a distance between a reference surface and a surface to be measured, including a wavelength reference element configured to include a gas cell in which a plurality of types of gases having absorption lines different from each other are sealed, and a processing unit configured to set a wavelength of light emitted by a light source to a plurality of different wavelengths corresponding to a plurality of different absorption lines by using the wavelength reference element, control a phase detection unit to detect a phase corresponding to an optical path length between the reference surface and the surface to be measured for each of the plurality of different wavelengths, and perform processing of obtaining the distance.

Abstract: A lightwave interference measurement apparatus includes a wavelength-variable laser which periodically performs wavelength scanning between first and second reference wavelengths to emit light beam, a wavelength-fixed laser which emits light beam having a third reference wavelength, a light beam splitting element which splits the light beams into reference light beam and light beam under test, a phase detector which detects a phase based on an interference signal of the reference light beam and the light beam under test, and an analyzer which sequentially determines an interference order of the third reference wavelength based on the third reference wavelength, first and second synthetic wavelengths, an integer component of a phase change amount in the wavelength scanning, and interference orders of the first and second synthetic wavelengths, and calculates an absolute distance between the surface under test and the reference surface.

Abstract: The present invention provides a measurement apparatus which measures a distance between a reference surface and a surface to be measured, including a wavelength reference element configured to include a gas cell in which a plurality of types of gases having absorption lines different from each other are sealed, and a processing unit configured to set a wavelength of light emitted by a light source to a plurality of different wavelengths corresponding to a plurality of different absorption lines by using the wavelength reference element, control a phase detection unit to detect a phase corresponding to an optical path length between the reference surface and the surface to be measured for each of the plurality of different wavelengths, and perform processing of obtaining the distance.

Abstract: A lightwave interference measurement apparatus includes a wavelength-variable laser which periodically performs wavelength scanning between first and second reference wavelengths to emit light beam, a wavelength-fixed laser which emits light beam having a third reference wavelength, a light beam splitting element which splits the light beams into reference light beam and light beam under test, a phase detector which detects a phase based on an interference signal of the reference light beam and the light beam under test, and an analyzer which sequentially determines an interference order of the third reference wavelength based on the third reference wavelength, first and second synthetic wavelengths, an integer component of a phase change amount in the wavelength scanning, and interference orders of the first and second synthetic wavelengths, and calculates an absolute distance between the surface under test and the reference surface.